| OPRTase | phosphoribosyltranferase |
|---|---|
| OPS | Open Pulled Straw |
| OPSI | Overwhelming Post-Splenectomy Infection |
| OPT | o-Phtalaldehyde |
| OPU | Ovum pick-up |
| OPU | oocyte pick-up |
| OPV | Oral Polio Vaccine |
| OPV | Oral Poliomyelitis Vaccine |
| OPV | Oral Poliovirus Vaccine |
| OPV | Orthopoxvirus |